Virtual Function in C++

最新推荐文章于 2020-10-08 17:35:26 发布

转载最新推荐文章于 2020-10-08 17:35:26 发布 · 473 阅读

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本文通过一个具体的C++示例介绍了虚函数的概念及其工作原理。文章展示了如何通过虚函数实现多态，使得基类指针可以调用派生类中重定义的方法。同时，也对比了虚函数与非虚函数在运行时的不同行为。

//  ---------https://www.geeksforgeeks.org/virtual-function-cpp/

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

class base{
public:
	virtual void print(){
		cout<<"print base class"<<endl;
	}
	void show(){
		cout<<"show base class"<<endl;
	}
};
class derive:public base{
public:
	void print(){
		cout<<"print derived class"<<endl;
	}
	void show(){
		cout<<"show derived class"<<endl;
	}
};

int main(int argc, char const *argv[])
{
	base *bptr;
	derive d;
	bptr= &d;
	bptr->print();//Virtual function，所以调用 derived class

	bptr->show();//non-virtual function 调用base class
	return 0;
}

输出：

A virtual function a member function which is declared within base class and is re-defined (Overriden) by derived class.When you refer to a derived class object using a pointer or a reference to the base class, you can call a virtual function for that object and execute the derived class’s version of the function.